High Pressure Electroluminescent TPC studies @ CIEMAT/IFAE Roberto Santorelli On behalf of I. Gil-Botella, E. Calvo, S. Jimenez Cabre, C. Palomares, A. Verdugo (CIEMAT-MADRID) O. Ballester, A. Garica-Soto, J. Illa, A. Lostao-Viñolas, T.Lux, F. Sanchez (IFAE-Barcelona) Advances in Neutrino Technology 2013, May 9-12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe General concept Electroluminescence (EL) detectors have a wide range of applications Several gas TPCs (both Ar and Xe researches) have been developed in a joint R&D activity by CIEMAT (Madrid) and IFAE (Barcelona) (Ar and Xe scintillation studies…) Main research line: medium size (110x200 mm) High-Pressure Gas Xe TPC with 25 APDs Combined energy resolution and tracking studies R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Example I: simple setup for QE studies (GXe) 241Am R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe EL signal R.Santorelli - ANT 2013, May 12 Lake Tahoe

Example II: small EL-TPC for spectroscopy studies (GAr) UV1 VIS1 VIS2 VUV1 UV2 UV IR VIS VUV R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe EPL, 91 (2010) 62002 GAr LAr R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe EL signals Va=1.5 kV , Vk=0 Va=2.5 kV , Vk=0 Va=3.0 kV , Vk=0 Va=3.0 kV , Vk=3.0 kV R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Main R&D activity Excellent performances of the gas TPCs in respect of energy resolution have been proved Limited knowledge about their tracking capabilities on larger scale Study of an APD readout for EL detectors Goal: Good energy resolution and investigation of possible tracking capabilities at the same time R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Experimental Setup HP TPC (30 cm long, 30 diameter) HV power supplies (20 and 35 kV) Preamp, ADC, APD power supply Cosmic ray trigger Xenon recovery system Getter PMT power supply Vacuum pump system R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe “CIFA” chamber 7 mm 110 mm 200 mm R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Readout array Array of 5x5 S8664-SPL APDs from Hamamatsu (5x5 mm2) powered independently Pitch 15 mm 2 PMTs for t0 measurements 3 custom made preamp/shaper boards V1740 CAEN ADC for digitization DAQ based on Midas R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Previous Studies Small HP chamber with 5 APDs All APDs at the same voltage Allowed to develop readout electronics Excellent energy resolution achieved xenon (8.2 ± 0.1)% FWHM J.Phys.Conf.Ser.309, pp. 012008.2011 R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Vertex Distribution Am-241 X-ray source (installed at the center of the cathode) Pressure: 2 bar Drift field: 200 V/cm/bar EL field: 4.5 kV/cm/bar Likelihood fit using light profile model for energy and position reconstruction R.Santorelli - ANT 2013, May 12 Lake Tahoe

First Results: Energy Resolution 13.9+17.8+20.8 keV 26.4+30 keV 8.7 FWHM @ 59.5 keV 59.5 keV A.U. Maximum signal in one of the 9 APDs in the center Signal summed over 24 APDs No correction yet for drift/diffusion, attachment…etc  Room for improvement R.Santorelli - ANT 2013, May 12 Lake Tahoe

First Results: Energy Resolution 8.2 FWHM @ 59.5 keV A.U. Maximum signal in the central APD R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe INTERCALIBRATION Problems: APDs gain very sensitive to the temperature and the voltage. The set up makes challenging to calibrate the APDs one by one. Solution: Intercalibration based on the position simmetry Key point  Use symmetry in light deposition around the maximum: It quantify the difference of energy between APDi and APDj when the maximum signal is in the one between them. 59.5 keV X-ray peak of 241Am used. R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe For events where the energy deposition in the middle APD is maximum, Aij should be 0 (assuming a symmetric EL shower). Due to different APD gains this Aij≠0. Correct these Ei and Ej using a calibration factor to avoid this problem. where After calibration: This αij should tend to one and A’ij to zero after calibration is done. R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Assymetry before calibration: Assymetry after calibration: A’ij tends to zero. Behavior of some of the alpha coeficients during calibration steps: Clear tendency of α to 1 R.Santorelli - ANT 2013, May 12 Lake Tahoe

INTERCALIBRATION: Preliminary results 242Am spectrum (when the energy deposition is maximum in one of the 9 central APDs): No calibration: Calibration (1st iteration): Calibration (2nd iteration): RE=13.12% RE=9.35% RE=9.04% The intercalibration process improves the resolution as we expected. R.Santorelli - ANT 2013, May 12 Lake Tahoe

First Results: Parameter Scan R.Santorelli - ANT 2013, May 12 Lake Tahoe

First Results: Tracking Cosmic rays trigger Very primitive cluster finder R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe First Results: T0 Sum of all waveforms over all events Possible to vary drift distance t between external trigger and signal arrival allows to estimate drift velocity vd= ~0.17 cm/us (theory: 0.1 cm/us) Probably N2 impurity Clear peak in both PMTs at t≈0 PMT UP PMT DOWN Peak in the sum of all APDs  Can we see this on event by event basis??? Sum APDs t [s] R.Santorelli - ANT 2013, May 12 Lake Tahoe

R.Santorelli - ANT 2013, May 12 Lake Tahoe Summary and Outlook Different EL-TPCs built in collaboration between CIEMAT and IFAE EL-TPC with 25 APDs for high pressure XE-gas studies in operation Energy resolution 8.2% @ 60 keV (room for improvements) Preliminary track reconstruction proved Study for t0 detection on going R.Santorelli - ANT 2013, May 12 Lake Tahoe

CIEMAT LAr lab 450 liters liquid nitrogen dewar. 2 cryostats of 70 liters each, high vacuum graded, for liquid argon. Turbomolecular pump for high vacuum.

R.Santorelli - ANT 2013, May 12 Lake Tahoe Vis2 Vis1 UV2 UV1 Pe/25 R.Santorelli - ANT 2013, May 12 Lake Tahoe